'Ghost' vr0 causes panic

There's a revision of motherboard we use in our products that has a
'ghost' vr0 on it. I guess some but not all of the supporting logic is
wired. It shows up on the BIOS post and in NetBSD 4 and earlier, vr0
partly attaches but has a mac address of 00:00:00:00:00:00. With NetBSD 5,
it panics at boot time:

breakpoint(c0a580b2,c0c5b8b4,c0a7f240,c052416f,c0a7f240,1ffd103,0,bff2b150,0,200)
at netbsd:breakpoint+0x4
panic(c0a23fc0,0,c0c5b8d8,c0c5b8d4,c0c5b8d0,0,c0c5b8f8,c051e0cd,0,1) at
netbsd:panic+0x1b8
mpacpi_nonpci_intr(c12467e0,14,c0c5b938,c056daf2,1,fdffd000,100,0,c0c5b928,0)
at netbsd:mpacpi_nonpci_intr
intr_find_mpmapping(0,48,c0c5b9c8,c0c5b954,c0c5b950,14,b000000,0,0,12) at
netbsd:intr_find_mpmapping+0x61
pci_intr_map(c0c5ba3c,c0c5b9c8,0,0,c0c5b9b4,c0c5b9c0,0,0,c0b05bd4,c09e9a62)
at netbsd:pci_intr_map+0x99
vr_attach(ca962c30,cac32c1c,c0c5ba3c,c0c5ba78,c0c5ba3c,0,cac32c1c,c056ca20,ca95e000,0)
at netbsd:vr_attach+0x1f3
config_attach_loc(ca962c30,c0a6bad8,c0c5ba78,c0c5ba3c,c056ca20,c0471d00,c0c5baa8,c047e38c,30651106,2100087)
at netbsd:config_attach_loc+0x163
pci_probe_device(ca95e000,80009000,0,0,0,c081ff04,0,1,0,80009000) at
netbsd:pci_probe_device+0x240
pci_enumerate_bus(ca95e000,c081ff00,0,0,c0c5bb08,c0c5bb04,c0c5bb38,c056cdee,ca962c30,c09e73b1)
at netbsd:pci_enumerate_bus+0x187
pcirescan(ca962c30,c09e73b1,c081ff00,c04728ed,c0b05bd4,ca4ada40,ca962c30,ca95e000,2,8)
at netbsd:pcirescan+0x2c
pciattach(ca80fb18,ca962c30,c0c5bbdc,0,c0c5bbdc,10,ca962c30,0,c09e73b5,c09e73b5)
at netbsd:pciattach+0x18e
config_attach_loc(ca80fb18,c0a6b538,0,c0c5bbdc,c0570290,0,c0c5bbb8,c052b0d7,ca80fb18,c09e7615)
at netbsd:config_attach_loc+0x163
config_found_ia(ca80fb18,c09e7615,c0c5bbdc,c0570290,0,0,0,ca80fb18,1,c0c5bc00)
at netbsd:config_found_ia+0x32
mpacpi_scan_pci(ca80fb18,c0c5bbdc,c0570290,0,ca4aef50,c0c5bbdc,1,0,0,1) at
netbsd:mpacpi_scan_pci+0xa7
mainbus_attach(0,ca80fb18,0,c0471e7e,c09e6a7b,c09e6a7b,ca80fb18,0,c09e6a7b,c61000)
at netbsd:mainbus_attach+0x23c
config_attach_loc(0,c0a6b520,0,0,0,c61000,c0c5bc98,c0473424,0,c0a6b520) at
netbsd:config_attach_loc+0x163
config_attach(0,c0a6b520,0,0,c0c58014,c58000,c0c5bcb8,c0533c08,c09e6a7b,0)
at netbsd:config_attach+0x2c
config_rootfound(c09e6a7b,0,0,c0c58014,c58000,c0c58014,c0c5bce8,c04735cd,c0a79760,c61000)
at netbsd:config_rootfound+0x44
cpu_configure(c0a79760,c61000,c0c5bce8,c04238c4,c0b186c4,c0c58014,c0c5bce8,c04d3cb3,c0b33a60,c0c58014)
at netbsd:cpu_configure+0x28